That is an accepted alternative.
The default translation uses "gray" because "English" on Duolingo means "US English" for nearly all courses.
In translations into English, UK English is generally accepted as well, but you should expect to see US English.
(So when you see "pants", for example, it refers to outer garments, not underwear.)
Many words similar to French come directly from latin, others from Italian (piscina=πισίνα for example) and some of them come truly from French. It was fashionable for the rich to speak French in the previous century, and common folk put their twist on that. There are even some (somewhat obsolete) slang things like Σας μερσώ=I thank you.
A trivial knowledge: Pantalon/Παντελόνι comes from the name of a Venetian comedy character, Pantalone (who wore trousers) which comes from the Greek name Πανταλέων=πάντα (every) + λέων (lion), so it's actually a borrowing of a borrowing.